The invention relates to a readjustment device and to a method for a friction clutch, with the aid of which it is possible to check the functioning of the assembled readjustment device up to an end position, the end of the wear range.
To compensate for the occurrence of wear on friction linings, friction clutches can be provided with a force-controlled readjustment device. In this case, an unfavorable development, due to wear, in the contact force of a lever system, e.g. a diaphragm spring, acting on the pressure plate of the friction clutch is detected, and a readjustment is effected in accordance with the contact force. As an alternative, an incorrect clearance between the clutch housing and the lever system, which occurs when there is wear on the friction linings of the clutch disk, can be determined and corrected in accordance with the incorrect clearance. For correction, compensating means, such as ramp systems or threads, arranged between the pressure plate and the lever system are rotated.
DE 10 2009 035 225 A1 previously disclosed a friction clutch having a displacement-controlled readjustment device in which a pawl which moves axially in accordance with the distance between a lever system and a pressure plate acts on a pinion of a spindle mounted rotatably on the pressure plate, wherein a spindle nut mounted on the spindle rotates a ramp ring of a ramp system, said ramp ring being arranged between the pressure plate and the diaphragm spring, when the spindle is rotated, thereby reestablishing the original distance between the lever system and the pressure plate. During the stroke of a counter plate relative to the pressure plate, the pawl slides on the teeth of the pinion and, given a predetermined wear, engages in a tooth gap between two teeth. During the next opening process of the friction clutch, the pawl takes the pinion along positively and, in the process, rotates the pinion and hence the spindle, thereby causing the spindle nut to rotate the ramp ring by a corresponding angle and hence readjusting the friction clutch. During this process, the ramp ring can be rotated from an initial position, without readjustment for wear, as far as an end position, in which there is maximum readjustment for wear.
There is a constant need to check the functioning of the fully assembled readjustment device without an increased expenditure of time and without damaging the components of the readjustment device, thereby making it possible to ensure reliable functioning of the readjustment device.